Telephone-exchange system



Feb. 26, 1924.- 1,484,963

A. RAYNSFORD TELEPHONE EXCHANGE SYS TEM Filed Sept. 14. 1920 2Sheets-Sheet 1 Fig.

POLAR/Z50 A. RAYNSFORD TELEPHONE EXCHANGE SYSTEM v Filed Sept. 14 1920 2Sheets-5heet 2 Ari/2w Faynsford Patented Feb. 26, 1924.

PATENT OFFIQE.

UNETED STATES ARTHUR RAYNSFORD, OF NEW YORK, N. Y., ASSIGNOR TO WESTERNELECTRIC COM- PANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OFNEW YORK.

TELEPHONE-EXCHAN GE SYSTEM.

Application filed September 14, 1920. Serial No. 410,311.

To all whom it may concern:

Be it known that I, ARTHUR RAYNSFORD,

a citizen of the United States of America,

residing at New York, in the county of New York and State of New York,have invented certain new and useful Improvements in Telephone-ExchangeSystems, of which the following is a full, clear, concise, and exactdescription.

This invention relates to telephone exchange systems and moreparticularly to such systems in which connections between thesubscribers stations are established partly by means of automaticswitching apparatus and partly with the aid of an operator. Morespecifically, the invention relates to trunk circuits for use at a callindicator operators position. wherein link circuits equipped withautomatic ringing and means for actuating coin collect or messageregister equipment terminate, to extend calls to a second operatorsposition such as a rural position or the like.

It is a well-known practice to arrange link circuits so that a source ofautomatic ringing current is disconnected when a called subscriber, withwhose station the link circuit may be connected, responds. It is alsowell known to utilize the closure of a loop 30 at the called subscribersstation when the receiver is removed from the switch hook thereat, tooperate a current reversing relay in the link circuit which, in turn,causes the actuation of a coin collect or message register device at thestation of a calling subscriber. If the call indicator operator, atwhose position subscribers lines terminate, is also provided with trunkcircuits, extending to a. second operators position such as a ruralposition, it is obvious that it is not desirable to operate the currentreversing relay in the link circuit when the rural operator responds,since this would cause the operation of the coin collect or messageregister device at the calling subscribers station before the calledsubscriber had actually responded.

It is, therefore, an object of the present invention toprovide meanswhereby, when the link circuit at the first operators or call indicatoroperators position is connected with the trunk circuit extending to therural or second operators position, ringing current is automaticallytripped, a signal at the second or rural o-perators position isactuated, and an audible ring-back signal is connected to the trunk forthe purpose of informing the calling subscriber that the connection isprogressing.

Another object of the invention is to provide complete super-vision forthe operators at the first and second positions in handling traiiic ofthis nature.

A. further object of the invention consists in the provision of means ina system of this character whereby, if the operator at the firstposition disconnects before the operator at the second positiondisconnects, a busy potential will be placed upon the jack at the firstoperators position and the multiples thereof, until the operator at thesecond position disconnects.

One of the features of the invention consists in the provision of means,in a trunk circuit extending from a first to a second operatorsposition, for disconnecting a source of automatic ringing current from alink circuit, when the link circuit is connected to the trunk circuit,for lighting a lamp at the distant end of the trunk and for connectingan audible ring-back signal to the link circuit.

A further feature of the invention consists in the provision of manuallycontrolled means at the second operators position for rendering anormally conductively divided trunk circuit continuous for the purposeof actuating a current reversing relay in the connected link circuit andfor providing supervision for the operator at the second position.

It is thought that the invention will best be understood from thefollowing detailed description, reference being had to the accompanyingdrawings.

In the drawings, Fig. 1 shows a subscribers set and indicatesdiagrammatically, a non-numerical switch, a first and second selector bymeans of which a desired office may be selected, a repeater forrepeating impulses over a two-wire trunk to a selected manual ofiice anda link circuit at the manual ofiice for use in extending calls from astation such as 1, to subscribers lines and other trunk circuits leadingto other positions. The link circuit L, which terminates in a plug 78,is one of a plurality of link circuits which are located at the callindicator trunk leading to the desired oflice.

number indicating device. together with switching mechanism foroperating such device. Theindicating device and switching mechanism arenot shown being simply indicated by the rectangle 1, since they form nopart of the present invention, a complete description thereof beinggiven in the patentof Lundell-Van Amstel, No. 1,456,508, issued May 29,1923. v

Fig. 2 of the drawings shows a trunk circuit T which extends from thecall indicator operators position to the rural position. At the ruralposition a cord circuit 13 is provided (a portion only of which isshown), for the purpose of extending calls through the trunk circuit Tto subscribers stations (not shown) terminating at the rural operatorsposition. The trunk circuit T comprises a pair of talking conductors anda non-talking conductor. The talking conductors of the trunk circuit Tare normally discontinuous one of the talking conductors being normallyopen and the other of the talking conductors being normally inductivelyunited by means of the condenser 110. Fig. 2 also shows the station ofan or-.

dinary subscribefis set 101 terminating in a jack 102 at the callindicator operators position.

Assuming first, that the subscriber at station 1 desires connection witha manual subscriber, the operation will be as follows: lVhen the callingsubscriber removes his receiver from the hook, a circuit will becompleted to cause the operation of a line switch diagrammaticallyindicated at '2, which will connect the calling lineto a first selectorWhose brushes are shown at 3. He will then operate his dial to send anumber of impulses whereupon the selector will be operated to select atrunk in a certain level of the contact bank. The subscriber willthensend another set of impulses to operate the selector whose brushesare'indicated at 42 which will then operate to select an idle trunk in alevel of its contact bank. The calling subscriber has now selected apxidle description of the operation of the line switch and first andsecond selector switches, or oflice selectors, as they may be termed,has not been given since they may be of any of a number of types ofstep-by-step switches well-known in the art.

As soon as selector 42 has seized a trunk, a circuit is completed fromgrounded battery, right-hand winding of relay 4, inner right-handarmature and back contact of relay 5, upper left hand winding ofrepeating coil 43, over the upper side of the line, through thesubscribers substation apparatus, over the lower side of the line, lowerleft hand winding of repeating coil 43, inner left hand armature andback contact of relay 5, and the left-hand winding of peating coil 43,right-hand armature and front contact of relay 4, lower right-handwinding of repeating coil 43, winding of polarized relay 5, trunkconductor 11, lower left-hand winding of repeating coil 9, lefthandnormal contacts of relay 8, and the left-hand winding of relay '7 toground. Polarized relay 5 is not energized at this time since thedirection of flow of current therethrough is such as not to cause itsenergization. .Relay 7, is however, energized in this circuit and opensa circuit to impulse conductor 91-, but completes a circuit at itsalternate contact, which causes the operation of apparatus (not shown)necessary for the reception of the succeedingimpulses. Under the controlof relay 7, the apparatus, for receiving the succeedingimpulses from theimpulse sender, is actuated, whereupon an assignment lamp (not shown) islighted to inform the operator that the apparatus has been set. v

The operator upon observing the lighting ofthe assignment lamp,depresses an assigment key (not shown) thus completing circuits for thenumber indicating device (not shown), which indicates to the operatorthe number desired.- The depression of the assignment key causes certainrelays associated with the call indicator apparatus to be actuated,which in turn causethe relays 69 and 13 to be actuated in parallel overa circuit including conductor 70.

Assuming first thatthe number appear- 7 ing upon the call indicatingdevice represents the number of asubscribers line terminating ina jackat the call indicator operators position such as 101 shown in Fig. 2 ofthe drawings, the operator after noting the number will insert plug 78into jack 102 of the desired line. A circuit is then completed fromgrounded battery, lamp 80, winding of relay 67, left-hand armature andback contact of relay 81, sleeves of plug 78 and jack 102 and Winding ofcutiofl' relay 103 toground. Lamp 80 is lighted and relays 67 and 103are energized in this circuit. The energization of relay 103 removes thecalled subscribers control of his line relay in the well-knownmanner.Energization of relay 67 completes a circuit for the application ofringing current. This circuit is as follows; grounded battery, windingofrelay83, left-hand armature and back contact of relay 84, armature andback contact of relay 85, outer right-hand armature and front contact ofrelay 13 now energized in the manner described for the like numberedrelay 13, in the above mentioned disclosure, lowermost armature andfront contact of relay 67, and winding of relay 67 to ground asdescribed. The low resistance of relay 83 shunts out lamp 80 and thislamp is extinguished. The energization of relay 83 completes a circuitfrom a source of ringing current 90, Winding of relay 85, lower armatureand front contact of relay 83, rings of plug 78 and jack 102 over theloop of the called substation-101, tips of jack 102 and plug 7 8, upperarmature and front contact ofrelay 67 and'upper armature and frontcontact of relay 83 to ground. In response to the completion of thiscircuit, the bell at the called station is caused to ring. When thecalled subscriber answers, relay 85 operates and in so doing removes theshunt from about the winding of relay 84. Relay 84 is then energized andlocks up through its left-hand armature and front contact. Battery atthe left-hand armature and front contact of relay 84 serves to shuntdown relay 83. As soon as relay 83 deenergizes, the talking circuit iscompleted and the s'ubscribersmay converse.

As soon as relay 83 is deenergized current flow from the battery inrepeating coil 9 energizes a supervisory relay 87 and since relay 84isalso energized, a circuit is completed from grounded battery, windingof relay 8, armature and front contact of relay 87, right-hand armatureand front contact of relay 84 to ground. Relay 8 is energized in thiscircuit and reverses the direction of current flow in the incoming endof the link circuit L. This reversal of current operates polarized relay5 of the re peater R. The operation of relay 5 reverses the direction ofcurrent flow in the calling subscribers line for the purpose ofoperating a coin collect or message register device in a mannerwell-known in the art.

As soon as relay 67 was energized the apparatus necessary for actuatingthe number indicating device was restored to normal position and madeavailable for the use. with other link circuits such as L in the mannerdescribed in the heretofore mentioned disclosure.

When the conversation is completed and the calling subscriber hasreplaced his receiver, line relay 7 is deenergized as a result of thedeenergization of line relay 4. Direct ground on the back contact of thearmature of relay 7 shunts down relay 69 and releases relay 69 which waspreviously energized in the manner described for the like numbered relay69, in the heretofore mentioned disclosure, causing in turn the releaseof relay 13. The circuit of relay 84 is therefore broken at the outerright-hand armature and front contact of relay 13 and the shunt isremoved from about lamp 80, causing this lamp to burn steadily as adisconnect signal. The operator thereupon removes the plug 7 8 from jack102. The link circuit L is then free for use with other connections.

.It will next be assumed that a number appears upon the call indicatordevice at the call indicator operators position, which is of such acharacter as to indicate that a connection with a rural subscriber isdesired. The call indicator operator thereupon inserts plug 78 of thelink circuit L into jack 104 of the trunk circuit T leading to the ruraloperators position, whereupon relays 105 and 67 are energized and lamp80 is lighted over a path extending from grounded battery, lamp 80,winding of relay 67, back contact and left-hand armature of relay 81,sleeves of plug 78 and jack 104, Winding and left-hand normal contactsof relay 105, and back contact and outer left-hand armature of relay 117to ground. Relay 105 in attracting its left hand armature locks up tobattery on the sleeve of plug 78. Relay 67 in operating completes acircuit for the application of ringing current. This circuit is asfollows: grounded battery, winding of relay 83, left hand armature andback contact of relay 84, armature and back contact of relay 85, outerright-hand armature and front contact of relay l3, lowermost armatureand front contact of relay 67, winding of relay 67, back contact andleft-hand armature of relay 81, sleeves of plug 78 and jack 104, windingof relay 105, and left-hand alternate contacts of relay 105 to ground.The low resistance of relay 83 shunts out lamp 80 and this lamp isextinguished. The energization of relay 83 completes a circuit from thesource of ringing current 90, winding of relay 85, lower armature andfront contact of relay 83, ring contacts of plug 78 and jack 104, backcontact and inner left-hand armature of relay 112 and resistance 113 togrounded battery. Relay 85 immediately energizes, and in so doingremoves the shunt from about the winding of relay 84. Relay 84 is thenenergized and locks up through its left hand armature and front contact.Battery at the left-hand armature and front contact of relay 84 operatesto shunt down relay 83. Relay 83 in retracting its armatures renders theoutgoing end of the link circuit L continuous.

As heretofore described relay 105 was operated and locked up as soon asplug 78 was inserted into jack 104. Relay 105 in attracting its outerright-hand armature completes a circuit through the right-hand ar- 106,inner right-hand armature and front contact of relay 105, back contactand outer left-hand armature of relay 112, condenser 109, tips of jack104 and plug 78, upper alternate contacts of relay 67, upper normalcontacts of relay 83 and upper right-hand winding of repeating coil 9 toground. The tone passing through the upper right-hand winding ofrepeating coil 9 induces a corresponding tone in the left-hand windingof repeating coil 9, which passes over the talking conductors to thecalling subscriber at station 1 in a manner well-known.

The operator at the rural position noting the trunk signal 114, insertsplug 119 ofthe cord circuit T, whereupon relay 117 of the trunk circuitT is operated. The path for the energization of relay 117 extends fromground, throughthe winding of relay 117, sleeves of jack 116 and plug119, resistance 120, and supervisory lamp 121 to grounded battery. Relay117, in operating, connects battery through resistance 118, frontcontact and right-hand armature of relay 117 to conductor 140, so thatin case the call indicator operator disconnects before the ruraloperator and relay 105 releases, a busy test will be placed on thesleeve of the trunk jack 104 and the multiples thereof. Relay 117 inoperating also completes a circuit for relay 112 over a path extendingfrom ground, outer left-hand armature and front contact of relay 117,and winding of relay 112 to grounded battery. Relay 112 in attractingits right-hand armature locks up to ground at the outer right-handarmature and front contact of relay 105 and opens the circuit for trunksignal 114, thereby extinguishing said signal. Relay 112 in operatingalso disconnects the tone from the source 107, from the trunk circuit Tand renders the tip talking conductor of the trunk circuit T continuous.At the inner left-hand armature and back contact of relay 112, thebattery, through resistance 113 for tripping the ringing current, isdisconnected from the trunk circuit T.

As soon as relay 112 attracts its outer left-hand armature, supervisoryrelay 122 of the cord circuit B is operated over a path extending fromground, upper righthand winding of repeating coil 9, upper normalcontacts of relay 83, upper alternate jack 104, resistance 108 outerleft-hand armature and front contact of relay 112 rings of jack 116 andplug 119 winding of relay 122 and lower left-hand winding of repeatingcoil 123 to grounded battery. Relay 122 in operating shunts out lamp 121in the well known manner and provides supervision for the answering endof the cord circuit B. When relay 122 is operated, relay 117 is heldenergized by battery through resistance 130 and the contact'sof relay122.

The operator may now actuate the listening key 141 for the purpose ofascertaining the number desired and upon being informed of such numberinserts the calling plug of the cord circuit B (not shown) into the jackof a line (not shown) and completes the call in the well-known mannerwhereupon supervisory lamp125 lights.

ing station by actuating key K of the trunk circuit T. Actuation of keyK completes a circuit for relay 115, which relay in operating locks upover a path extending from grounded battery, winding and right-handarmature and front contact of relay 115, front contact and iinner{lefthand armature of relay 117 to ground. The relay 115 in attractingits left-hand armature bridges resistance 111 around condenser 110.

Supervisory relay 87 of the link circuit L is then energized over a pathextending from grounded battery, lower right-hand winding of repeatingcoil 9, Winding of relay 87, lower normal contacts of relay 88, rings ofplug 78 and jack 104, resistance 111, front contact and left-handarmature of relay 115, tips of jack 116 and plug 119' and upperleft-hand winding of repeating coil 128 to ground. Relay 87 in operatingcompletes a circuit for relay 8 over a path extending from groundedbattery, winding of relay 8, front contact. and armature of relay 87,righthand armature and front contact of relay 84 to ground. Relay 8 inattracting its armatures reverses the direction of current How in theincoming end of the link circuit L. This reversal of current oggratespolarized relay 5 of the repeater The operation of relay 5 reverses thedirection of current flow in the calling subscribers line for thepurpose of operating a coin collect device or a message register devicein a manner well-known in the art.

the calling subscriber has replaced his receiver, line relay 7 isdeenergized as a result of the deenergization of line relay 4. Directground on the back contactof the armature of relay 7, causes the releaseof" relay 13 in the manner described in the heretofore mentioneddisclosure. The circuit of relay 84 is thereupon interrupted at theouter right-hand contact and armature of relay 13 and the shunt isremoved from lamp causing this lamp to burn steadily as a disconnectsignal. The operator may then remove plug 78 from jack 104 whereupon thelink circuit L is free for use with other connections.

\Vhen the called subscriber replaces the receiver upon the switchhook,supervisory relay 124 of the cord circuit B deenergizes thereby lightingsupervisory lamp 125 which serves as a disconnect signal.

If the call indicator operator disconnects first the bridge across thelink circuit at the call indicator position is opened thereby causingthe deenergization'o-f supervisory relay 122 at the rural operatorsposition. Itelay 122 in deenergizing removes the shunt from supervisorylamp 121, causing this lamp to light, which indicates to the ruraloperator that the operator at the call indicator position hasdisconnected. Removal of the plug 7 8 at the call indicator positlon,from the jack 104 also causes the release of sleeve relay 105 associatedwith the trunk circuit T. Closure of the left-hand normal contacts ofrelay 105 connects battery, present on conductor 140, to the sleeve ofjack 104 and multiples thereof, thereby rendering the trunk busy. Whenthe rural operator disconnects, relay 117 releases. Relay 1 17 inretracting its left-hand armatures, opens the circuits for relays 112and 115 and in retracting its right-hand armature removes battery fromconductor 140, thereby restoring the trunk circuit T to normal.

If the rural operator disconnects first, relay 117 releases, therebyopening the locking circuit for relay 115. When the call indicatoroperator disconnects, relay 105 releases causing in turn the release ofrelay 112, whereupon the trunk circuit T is restored to normal.

What is claimed is:

1. In a telephone system, an incoming line, current reversing meansassociated therewith, a trunk circuit, means associated with saidincoming line for applying ringing current to said trunk circuit, asignal for said trunk circuit, a source of tone, means effective uponthe connection of the incoming line to the trunk circuit to trip saidringing current without operating said current reversing means, andmeans in said trunk circuit also effective upon the connection of theincoming line to the trunk circuit to apply tone from said source tosaid incoming line and to. actuate said signal.

2. In a telephone system, an incoming line, current reversing meansassociated therewith, a trunk circuit, means associated with saidincoming line for applying ringing current to said trunk circuit, asigna for said trunk circuit, a source of tone, means operative inresponse to the connection of the incoming line to the trunk circuit totrip the ringing current without operating said current reversing means,and a relay in said trunk circuit operative in response to theconnection of the incoming line to said trunk circuit to apply tone fromsaid source to said incoming line to actuate said signal.

3. In a telephone exchange system, an in coming line, an outgoing lineincluding a pair of talking conductors and a sleeve conductor, means forestablishing a connection between said lines, a signaling circuitcompleted upon the establishment of said connection, means including asource of current normally connected to one of the talking conductors ofsaid outgoing line for rendering said signaling circuit inefiective uponthe establishment of said connection, a source of tone supply, a signal,and a single relay in the sleeve conductor of said outgoing lineoperated when said connection is established for connecting said sourceof tone supply to said incoming line and for operating said signal.

4. In a telephone system, a subscribers line, a trunk circuit, a signal,a source of tone associated with said trunk circuit, an incoming line,means for establishing a connection between said incoming line and saidsubscribers line or between said incoming line and said trunk circuit,current reversing means associated with said incoming line, meansassociated with said incoming line for applying ringing current to saidtrunk line, means for tripping said ringing current and operating saidcurrent reversing means when said incoming line is connccted to saidsubscribers line, and means for tripping said ringing current, forconnecting said source of tone to said incoming line, for preventing theoperation of said current reversing means and for lighting said signalin response to the connection of said incoming line to said trunkcircuit.

5. In a telephone exchange system, a trunk circuit extending from afirst to a second operators position, a condenser normally dividing thetrunk circuit into two sections, a link circuit terminating at saidfirst position, a signal, a source of tone supply, a current reversingrelay associated with said link circuit, a supervisory relay associatedwith said link circuit, a source of ringing current associated with saidlink circuit adapted to be connected to said link circuit when said linkcircuit is taken for use, means responsive to the connection of IUD withsaid trunk circuit for disconnecting said source of tone supply fromsaid trunk circuit and for extinguishing said signal,

7 and operator controlled means for providing a path around saidcondenser so as to operate said supervisory relay to operate saidcurrent reversing relay.

6. In a telephone exchange system, a first position and a secondposition, a trunk circuit extending between said positions andterminating at each position in a jack, said circuit comprising a pairof talking conductors and a non-talking conductor, a link circuit ateach of said positions, a supervisory signal for each of said linkcircuits, a signal for the trunk circuit at said second position, arelay connected to the sleeve of the jackat the first position energizedwhen the link and trunk circuits are connected at the first position foroperating said trunk signal, means for extinguishing said signal whenthe link circuit at the second position is connected to the trunkcircuit, and means including said relay for rendering said ack at saidfirst position busy if the operator at the first position disconnectsfirst.

7 In a telephone exchange system, a first operators position,a secondoperators position. a trunk circuit extending between said positions,said trunk circuit having a pair of talking conductors and anon-talking, conductor, a signal at said second position, a link circuitat each of said positions connected to said trunk, a relay at each ofsaid positions connected to the non-talking conductor of said trunk, anda circuit completed through contacts of said relays for rendering thetrunk busy if the operator at the first position disconnects beforetheop erator at the second position disconnects.

8. In a telephone exchange system, a first operators position, a secondoperators position, a subscribers line terminating at said firstposition, a trunk line extending between said positions, a signal atsaid second posi-- tion for said trunk line, an incoming link circuitterminating atsaid first position for extending calls thereover to saidsubscribers line or over said trunk line, a current reversing relaytherein, means for operating said relay when a called subscriberanswers, a cord circuit at said second operators position, a supervisoryrelay therein, means for actuating said signal when said link circuit isconnected to said trunk line, means for extinguishing said signal andactuating said supervisory relay when said cord circuit is connected tosaid trunk line, and operator controlled means for actuating saidcurrent reversing relay.

In witness whereof, I hereunto subscribe my name this 11th day ofSeptember A. D., 1920.

ARTHUR BAYNSFORD.

